The generation of developmental fog is a phenomenon wherein densities in unexposed areas of a silver halide photographic light-sensitive material (which is abbreviated as "sensitive material" hereinafter) are increased by development-processing. This phenomena is more apt to generate more fog the higher the sensitivity of the sensitive material, the longer the sensitive material is stored, and the higher the temperature and the humidity of an atmosphere in which the sensitive material is stored. However, it is desirable to reduce the generation of developmental fog because it causes deterioration of photographic properties, e.g., lowering of image contrast, etc.
In order to suppress the generation of developmental fog, a means of adding a so-called antifoggant to a sensitive material or a developing solution has been employed, and a great number of compounds are known to function as antifoggants. Among those compounds, 1-phenyl-5-mercaptotetrazole is especially famous as an antifoggant. However, such a compound frequently causes a considerable decrease in sensitivity. Further, 1-phenyl-5-mercaptotetrazole derivatives whose phenyl group is substituted with two carboxyl groups are also known to function as the antifoggant, as described in U.S. Pat. No. 3,266,897. However, as can be seen in the examples of such a patent specification, those derivatives can make only small contribution to the prevention of developmental fog generated in sensitive materials which are stored in an atmosphere of high temperature and high humidity.
Furthermore, U.S. Pat. No. 4,328,302 discloses 1-phenyl-5-mercaptotetrazole derivatives whose phenyl group have certain substituents. However, such an invention relates to an improvement in quality of half tone dots in infectious development and to prevention against generation of fringe and therefore, it differs entirely from the spirit of this invention.